1. Field of the Invention
The present invention relates to an ink jet printer head.
2. Description of the Related Art
There is an actuator of a head equipped in an ink jet printer, which expands and restores the capacity of many ink storing chambers formed inside the actuator using a piezoelectric element installed corresponding to each of the ink storing chambers, and which applies pressure to the ink inside the ink storing chamber. In this way, the actuator discharges the ink from an ink discharge hole formed in each of the ink storing chambers to the external i.e., onto the recording sheet.
As one example of such an actuator, this is an actuator provided with: a cavity plate in which the ink storing chambers and ink flow paths to supply the ink to the ink storing chambers are formed; and a nozzle plate in which fine ink discharge holes are formed.
The ink discharge holes may be arranged tandem in two rows along a longitudinal direction of the cavity plate at a central surface portion of the cavity plate. Along this tandem direction of the ink discharge holes, two ink flow paths are formed on both peripheral surface portion of the cavity plate. The ink storing chambers store the ink supplied from these ink flow paths, and introduce the ink to the ink discharge holes, such that a plurality of grooves connecting the ink flow paths with the ink discharge holes are arranged along the tandem direction of the ink discharge holes.
These ink storing chambers are separated from each other by respective one of separating walls, each of which is called as a beam. By accurately keeping the width, the height and the arrangement interval (the pitch) of the beam to be predetermined values respectively, the variations of the capacities of the ink storing chambers can be reduced, and that the ink discharge ability can be improved.
However, since the above mentioned cavity plate is formed by injection-molding ceramic such as alumina and then sintering the ceramic, it is necessary to apply a polishing process after the molding and sintering processes, so that it is difficult to keep the width, the height and the arrangement interval of the beam to be predetermined values respectively.
Namely, in a case of forming the beam in a perpendicular wall shape, since the physical or mechanical strength at a root portion of the beam is weak enough to be easily broken, the beam is formed with a certain taper angle. In such a case, there is raised a problem that the width of the beam is changed by the polishing amount.
Further, in a case of fixing the cavity plate onto the piezoelectric element member, it is necessary to adhere a partition plate called as a diaphragm on the cavity plate. In such a case, there is raised a problem that the adhesive agent coated on the beam tends to flow into the grooves from the beam in the taper shape, and the capacity of the ink storing chamber is reduced.